1. Field
The present disclosure relates to a printer that performs desired printing on a print-receiving medium.
2. Description of the Related Art
There are known printers that perform printing utilizing a driving force of a pulse motor. In this printer, feeding means (a roller driving motor) feeds a print-receiving medium (cover film) by a driving force of a pulse motor (roller driving motor), and a thermal head performs the desired printing on the print-receiving medium thus fed. The pulse motor rotates at a predetermined angle by applying a single pulse signal (switching the excitation phase to the next state), and the rotation speed is controlled by shortening and lengthening the interval at which the pulse is applied. The thermal head comprises a plurality of heating elements arranged in a direction orthogonal to the transport direction. This plurality of heating elements performs printing by forming dots on the respective printing lines of the print-receiving medium. Specifically, in response to the print-receiving medium being fed by the feeding means and the printing lines of the print-receiving medium sequentially passing the positions of the heating elements, the conduction mode of the heating elements is sequentially switched on a per line print data (section of print data divided into one of the printing line units) basis. With this arrangement, it is possible for the thermal head to perform printing at a printing speed that matches the feeding speed of the print-receiving medium by the feeding means.
In the printer that uses the pulse motor, the coordination mode in a case where feeding and printing are performed in coordination as described above may be switched between one coordinated state wherein the pulse motor rotates at a relatively fast rotation speed and another coordinated state wherein the pulse motor rotates at a relatively slow rotation speed, executed to correct the print length so that it is shorter. At such a time, when the conduction of the plurality of heating elements and the driving of the pulse motor are controlled in coordination and the mode is switched from the one coordinated state to the other coordinated state or conversely from the other coordinated state to the one coordinated state, the possibility exists that the input of the pulse signal and the switching of the excitation phase will become mismatched if there is a large difference in the rotation speeds of the pulse motor, causing difficulties in smooth motor operation.